It would appear that maybe MP3s ARE the reason for lower music sales, just not in the way you think…  Are your compressed audio files driving you away from music???
Much of the information left out during MP3 compression is at the very high and low ends, which is why some MP3s sound flat. Without enough low end, ‘you don’t get the punch anymore. It decreases the punch of the kick drum and how the speaker gets pushed when the guitarist plays a power chord.’ The inner ear automatically compresses blasts of high volume to protect itself, so we associate compression with loudness. After a few minutes, constant loudness grows fatiguing to the brain. Though few listeners realize this consciously, many feel an urge to skip to another song.